You can use this function almost anywhere across macOS, except for web pages and apps that override your right-click menu, such as Google Docs or a game. How to use and modify the Dictionary app ...

The Dictionary and the Thesaurus help find the most appropriate word for a context. Here are the top 5 free Dictionary & Thesaurus apps for Windows, which you can use without internet.

Today, version 2.2 of the app brings a full dictionary with it. This matches the functionality of Apple's own iBooks app, but the Kindle implementation is even a little better.